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2 votes
Write (2 – i)4 in simplest a + bi form.

2 Answers

1 vote

Answer:

8 - 4i

Explanation:

(2- i)4

= (2 × 4 - 4 × i)

= 8 - 4i

User Jefdaj
by
9.0k points
7 votes

Answer:

Answer : 21 - 20i

Explanation:


{(2 - i)}^(4) = (2 - i) {}^(2) (2 - i) {}^(2) \\ \\ = (4 - 2i - {i}^(2) )(4 - 2i - {i}^(2) )

remember i² is -1 :


= (4 - 2i - ( - 1))(4 - 2i - ( - 1)) \\ = (5 - 2i)(5 - 2i) \\ \\ = (25 - 20i + 4 {i}^(2) ) \\ = (25 - 20i + 4( - 1)) \\ = (25 - 20i - 4) \\ = 21 - 20i

User Alexbrn
by
7.6k points

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